SpamAssassin™ is a mail filter that identifies spam. Using its rule base, SpamAssassin™ uses a wide range of heuristic tests on mail headers and body text to identify "spam", also known as unsolicited commercial email.

The spam-identification methods that SpamAssassin ™  utilizes includes:

·         Header Analysis: Spammers use a number of tricks to mask their identities, and to fool you into thinking they've sent a valid e-mail, or fool you into thinking you must have subscribed at some stage. SpamAssassin tries to spot these.

·         Text Analysis: Again, spam mails often have a characteristic style (to put it politely), and some characteristic disclaimers and CYA text. SpamAssassin can spot these, too.

·         Blacklists: SpamAssassin supports many useful existing blacklists, such as mail-abuse.com, ordb.org or others.

·         Razor: Vipul's Razor is a collaborative spam-tracking database, which works by taking a signature of spam messages. Since spam typically operates by sending an identical message to hundreds of people, Razor short-circuits this by allowing the first person to receive a spam to add it to the database -- at which point everyone else will automatically block it.

Once identified, the mail can then be optionally tagged as spam for later filtering using the user's own mail user-agent application.

SpamAssassin requires very little configuration; you do not need to continually update it with details of your mail accounts, mailing list memberships, etc. It accomplishes filtering without this knowledge, as much as possible.